1. Field of the Invention:
The present invention relates to a portable hand-held manually operated apparatus for performing dry printing on miscellaneous surfaces and objects, for example to dry print identification indicia for trade branding or to discourage theft.
2. Brief Description of the Prior Art:
No practical solutions to this kind of problem have been proposed in the prior art. Although hot embossing is a well known process, most traditional hot printing machines have been relying on C-shaped frames provided with a lower platen on which the workpiece must be positioned to carry out the printing operation. Such a hot printing machine is disclosed in U.S. Pat. No. 4,628,810 (Chan) issued on Dec. 16, 1986, showing a C-shaped press bringing a heated die in indirect contact with the workpiece through an embossing film. The combination of heat and pressure applied to the film causes the transfer to the surface of the workpiece of a part of a transfer material coating the film. Some embossing of the workpiece surface may also be performed as a function of the process parameters, such as temperature, pressure and application time, to create a more durable marking.
Although the prior art apparatus as described in U.S. Pat. No. 4,628,810 enables application of a high force to produce the pressure required for proper printing and embossing on the workpiece surface, it presents the following drawbacks:
it produces a limited stroke and restricts the size of the workpiece since that workpiece has to be inserted between the die and the platen; PA1 it is always required to bring the workpiece to the workstation; and PA1 its rigid assembly does not provide for self-adjustment to sloped or non planar surface, thus yielding an uneven pressure to the surface and poor printing quality. PA1 the air convection passage is a vertically extending air convection passage in which convection air flows from bottom to top; PA1 the frame structure has two opposite sides, and the handle portion comprises two handles mounted on the two opposite sides of the frame structure, respectively, each handle being spaced apart from the die member/heat source assembly to define the air convection passage; PA1 the frame structure is hollow, and the two opposite sides of the frame structure are open to create an empty space between the two handles; PA1 the portable hand-held manually operated dry printing apparatus further comprises a ribbon holder mounted on a top portion of the frame structure for supplying a dry printing ribbon, and a ribbon guiding system (a) for guiding the ribbon from the ribbon holder along a path extending between the die member and a surface on which dry printing is to be performed to transfer, by heating, material from the ribbon to that surface, and (b) for returning the ribbon back to the ribbon holder; PA1 the ribbon holder comprises a ribbon cutter, and the ribbon is returned back to the ribbon cutter where used ribbon can be cut; PA1 the ribbon guiding system comprises a generally rectangular bottom plate defining a window, and two end notches for positioning and guiding the ribbon in front of the window; PA1 the die member is a dry printing and embossing die, the die member comprises an electronically programmable matrix of individual heating elements forming an array of selectively heatable pixels, the die member comprises compliant heat conductive material to adapt to an irregular surface on which dry printing is performed; PA1 the dry printing apparatus comprises a housing forming the frame structure, this housing being shaped to define the handle portion and being made of molded plastic material; and PA1 the housing comprises a top wall with openings, side walls, and an open lower end to receive the die member/heat source assembly, and the air convection passage extends through a space between the side walls and the die member/heat source assembly, and the openings of the top wall. PA1 the portable hand-held manually operated dry printing apparatus comprises a housing forming the frame structure, shaped to define the handle portion, and comprising a top wall and an open lower end to receive the heat source, the die member and the guide member; PA1 the guide member comprises a tubular member telescopically mounted in the open lower end between the extended and retracted positions; PA1 the guide member comprises a lower end to be applied to the surface to be dry printed, and a spring member is interposed between the tubular member and the top wall of the housing for spring-biasing the tubular member toward the extended position; PA1 the tubular member comprises a top wall, the top wall of the housing is provided with a threaded hole, the dry printing apparatus further comprises a threaded rod screwed into the threaded hole of the top wall of the tubular member, and the threaded rod comprises a lower free end for abutting against the top wall of the tubular member to limit the stroke of the tubular member in the housing, whereby the amplitude of this stroke is adjusted by adjusting the longitudinal position of the threaded rod in the threaded hole; and PA1 the tubular member comprises two opposite openings, the housing comprises two opposite, inner protuberances extending in the two openings, respectively, the protuberances have smaller dimensions compared to the openings to enable telescopic movement of the tubular member in the housing between the extended and retracted positions, and the respective dimensions of the openings and protuberances determine the maximum amplitude of the telescopic movement of the tubular member in the housing. PA1 the guide member comprises a generally rectangular bottom plate defining a window, and a pair of parallel, spaced apart posts for mounting the generally rectangular bottom plate on the frame structure; PA1 the parallel, spaced apart posts are (a) telescopically mounted on the frame structure between the extended and retracted positions, and (b) spring biased toward the extended position by spring members interposed between the posts and the frame structure whereby (a) the posts are slidable on the frame structure from the extended position to the retracted position against the force exerted by the spring members to apply the die member to the surface to be dry printed through the window, and (b) the force exerted by the spring members returns the telescopic posts from the retracted position to the extended position after the dry printing operation is completed; PA1 the portable hand-held manually operated dry printing apparatus comprises stop members mounted on the posts and abutting against the frame structure to limit a downward stroke of the die member; PA1 the portable hand-held manually operated dry printing apparatus comprises means for adjusting the position of the stop members along the posts to thereby adjust the downward stroke.
U.S. Pat. No. 4,181,560 granted to Maitland on January 1.sup.st, 1980 shows a marking device featuring an open-ended housing and accepting a hot die foil stamping head. Still, this marking device is intended for mechanical operation and lacks appropriate film reel management, temperature control, and any other feature that would enable manual operation thereof, so that it could be brought to a site to mark objects in variable locations and positions without having to move these objects.
U.S. Pat. No. 4,904,334 (Honma et al.) granted on Feb. 27, 1990 discloses a hand-held manually operated apparatus for applying a transfer material on an image portion of a photocopy. A ribbon made of a film including transfer material is first brought into contact with the surface of the photocopy by a downward vertical displacement of a heated flat plate, which heated flat plate is subsequently sled over the film to apply the transfer material onto the desired area of the photocopy. Obviously, this apparatus has not been designed for printing and embossing operations due mainly to the absence of a replaceable embossing die and temperature control to provide adequate printing temperature for different films and workpiece materials or desired embossing depth. Also, such an apparatus does not provide the operator with a visual feedback to properly position an eventual printing die so as to print an indicia at a precise location on a workpiece. Moreover, the free end of the ribbon is not properly held to permit lifting and repositioning of the apparatus after each printing operation. Still, cutting of the ribbon is only possible after final use of the apparatus, by using a serrated portion of the closure cap.
The above discussed prior art demonstrates that no reasonably practical solution to the problem of hot embossing on miscellaneous objects in the field of identification or for any other purpose has been provided yet.